Great looking rifle . Did you have a post somewhere explaining how you "reamed" the fr.trunnion ? I'm curious as to how you did that and what about the undercuts inside the trunnion for the rivets to be mashed, that would make them around .020 shallower, would it not ?
Did you consider turning down the chamber OD to 22mm as an alternative ?

I didn't have a proper cutting head for a mill.
So, I resorted to a sanding drum with the flappers on a dremel.
It took some time and frequent checking with a mike.
But, I got an excellent tight fit.

The underside of trunnion needed some fitting for the larger
7.62 mag. The rivets in the magwell do have a longer way to go,
I used some longer 74 rivets I had for this. Also had to grind down the
mashed heads a little bit so the mag would clear. It's a tighter fit.
The feed ramp also needs taken down for the larger cartridge diameter.
More dremel and drum work.

Charter member-Busted Box Club est. 2006

"I will adhere to the Patriot Act, the one signed in 1776"- Marc Anderson

You will need to decide that, if you know how to grind steel you can go that route to take off the bulk of it, then finish it with files. Just becareful you don't get the steel too hot, you might change the temper of the steel

Any quality file will work, I wouldn't get any of those that places like Harbor Freight sells, the quality control is very poor. Get different ones like course, medium and fine.

"Government is not the solution to our problem, government is the problem" Ronald Reagan

I assume you used the milled Bulgy 7.62 bolt & carrier? The difference in the barrel setback into the trunnion and the bullet guide cam were no problem?

The reason I ask is the Bulgy AK74 has a long head bolt vs the shorter AK47/AKM in 7.62.
Just wondering about the bullet guide cam and the barrel setback etc.,.
All the barrel components lined up or did you have to rweork anything in terms of stacking because of the barrel setback?

thanks for the 20 questions answers., in advance.

I'm planning a sorta similar build but plan to turn the barrel down to 22mm. I have a milspec SLR95 chromelined barrel. It is AK74/AKM pattern on the FSB & GB but AK47 on the RSB so I'll turn that down to AK74 as well. I'm usng a base AK74 kit for my buid but a 7.62 bolt carrier and barrel.

AS FAR AS I CAN TELL YOU WOULD JUST SET THE BARREL BACK TO USE THE SHORTER 47 BOLT HEAD. I HAVE NOT DONE ONE YET BUT I HAVE A FEW 74 TRUNIONS AN WAS GOING TO USE THEM WITH BULDGY 223 BOLTS THAT ASIDE FROM THE FACE DIA ARE THE SAME AS A AKM BOLT AN IT LOOKS LIKE YOU NEED TO MILL DOWN THE BULLET GUIDE AN THE BOLT WILL ROTATE IN PROPERLY AN LOCK UP ON THE LUGS.

OBVIOUSLY THIS BUILD SHOOTS WITH A 74 TRUNION RUNNING A 47 BOLT. I KNOW THE BOLT WILL NOT CLEAR THE BULLET GUIDE AS IS I HAVE TRIED IT. THE BOTTOM OF THE BOLT BARELY HITS THE GUIDE.

LOOKING AT THE 74 GUIDE IT LOOKS LIKE ALL YOU NEED TO DO IS TAKE A SANDING ROLE OR BUR AN REPLICATE THE 7.62X39 GUIDE . I SEE NO REASON TO REMOVE IT. YOU NEED TO MILL /GRIND SOME CLEARANCE FOR THE X39 MAG TO ROTATE IN JUST UNDER THE LUGS AS WELL OR YOU CAN POSSABLY CLEARANCE THE MAGS IF YOU WANT MAGS SPECIFIC TO THE GUN.

IM PLANING ON DOING ONE 74 TRUNION TO GO ON ONE OF MY 6MM BRX VARIANTS IT WILL USE A OPEND UP X39 BOLT . I HAVE LOOKED INTO OPENING UP A 74 BOLT AN NOT SURE ITS DOABLE TO A 308 WIN / .470 FACE. IT MIGHT BE DOABLE TO A .444/X39 RIM HOWEVER.

I assume you used the milled Bulgy 7.62 bolt & carrier? The difference in the barrel setback into the trunnion and the bullet guide cam were no problem?

The reason I ask is the Bulgy AK74 has a long head bolt vs the shorter AK47/AKM in 7.62.
Just wondering about the bullet guide cam and the barrel setback etc.,.
All the barrel components lined up or did you have to rweork anything in terms of stacking because of the barrel setback?

thanks for the 20 questions answers., in advance.

I'm planning a sorta similar build but plan to turn the barrel down to 22mm. I have a milspec SLR95 chromelined barrel. It is AK74/AKM pattern on the FSB & GB but AK47 on the RSB so I'll turn that down to AK74 as well. I'm usng a base AK74 kit for my buid but a 7.62 bolt carrier and barrel.

I used the 74 bullet guide.
It's thicker, for the smaller round.
But, I ground it down to the 47 profile since there was plenty of meat on it.

I used the Bulgy 47 bolt and carrier.
There seemed to be no set-back issues.
The bolt lock-up proceeded well when head space was reached.
Otherwise, I admit, it felt a bit clunky.

Everything did align well in the end.
I was concerned about the gas block, and gas port alignment,
but, it matched up fine. The RSB has room for adjustment on the barrel
if need be. I wanted the bakelite lower to fit snug, as well as the top cover. And, it all went seamless.
The gas block, I pressed on until it was a nice snug fit, and the
gas port was right on.

My lucky day.
I would have turned my bbl down to fit the Bulgy 74 trunnion,
but, did it the other way around.
Honestly, I would suggest using a 7.62 trunnion if you have it.
I just didnt' have an extra. I stretched an '74' to a 47 orientation.
There is more work involved to make this work than you might anticipate.
So, just be aware.

Charter member-Busted Box Club est. 2006

"I will adhere to the Patriot Act, the one signed in 1776"- Marc Anderson

I used the 74 bullet guide.
It's thicker, for the smaller round.
But, I ground it down to the 47 profile since there was plenty of meat on it.

I used the Bulgy 47 bolt and carrier.
There seemed to be no set-back issues.
The bolt lock-up proceeded well when head space was reached.
Otherwise, I admit, it felt a bit clunky.

Everything did align well in the end.
I was concerned about the gas block, and gas port alignment,
but, it matched up fine. The RSB has room for adjustment on the barrel
if need be. I wanted the bakelite lower to fit snug, as well as the top cover. And, it all went seamless.
The gas block, I pressed on until it was a nice snug fit, and the
gas port was right on.

My lucky day.
I would have turned my bbl down to fit the Bulgy 74 trunnion,
but, did it the other way around.
Honestly, I would suggest using a 7.62 trunnion if you have it.
I just didnt' have an extra. I stretched an '74' to a 47 orientation.
There is more work involved to make this work than you might anticipate.
So, just be aware.

Thanks for the input. I do not mind lathing the barrel journal down or doing fitment work. I have done quite a bit of that.
I was more concerned over 5.45 bullet guide use and barrel setback as a AK74 bolt is longer than an AKM bolt in the lugs.
In theory this would require setting the barrel further back in the trunnion which in turn may impact the bolt camming off the AK74 bullet guide.
Also the 7.62 magazine fitment in the 74 trunnion., is a different lock up.

I built an AK74 kit using an AKM trunnion bolt & carrier & SLR95 barrel already but want to do a complete Bulgarian build with the matching trunnion this time. I'll have a friend engrave the bolt & carrier to match.